IMO, PN should call off induction of all surface warships and should go for all submarines. Its because PN has only one adversary and it is IN. In no way can PN even think of matching IN capabilities. In any war, the first target of IN will be to destroy karachi port and enforce blockade. No surface ship of Pakistan can ever challenge this blockade. And fighters like Su 30mki, Mig 29K because of their advance avionics and weapons will wipe out the entire surface fleet of PN in less than 2 days of war. And again Brahmos launched from ship with 290km range will clear the surface fleet of PN even before they could detect the ship that fired them and within next 2 years Brahmos will be available to launch from air as well. So in short capability of IN exceeds PN by many miles. And once all these surface ships gets wiped out, the morale of the PN will take a bad beating and even remaining 3+3 submarines will not be that effective then.
Now just imagine that PN has no surface ships but instead has 10-12 submarines. So in one go; Brahmos factor, Su-30mki factor, Mig 29K factor virtually vanishes for PN. The fight will now be of subsurface capability. Though IN will after inducting Scorpene submarines and fitting towed sonars in their frontline warships and also with their P-8 planes, will be way ahead of PN, but in the this case it will not be a cakewalk for IN and because most of this ships of PN will have AIP, it will not be easy to track their location and IN will have to search entire Arabian Sea and also some parts of Indian Ocean to track these ships, which will be a nut cracking job. And with good strategy, they can effectively deny the blockade as IN will have no clue how many subs they will be facing infront while imposing blockade and how many may surprise their own port back home.
In short, in later case IN will have to keep one part of their resources back home for security of their own ports.